This invention relates generally to optical interconnect driver circuits, and, more particularly to systems and methods for driving a light emitting semiconductor device.
In optical interconnect systems, when the interconnect channel density becomes many hundreds of interconnects and even greater per square inch, the thermal gradients and thermal dissipation in the interconnect elements themselves become a major issue. This undesirable trait costs the system even more energy to extract this thermal load from the interconnect component area, particularly when active cooling devices such as thermo-electric (Peltier) coolers are required.
The use of VCSELs for optical data links is well established in the art. The laser elements in these links are driven by a multitude of electronic devices at various power levels, data rates and duty cycles. Typically, these VCSEL systems are designed to switch or modulate within a linear region of lasing operation. This is accomplished by electrically biasing the laser element above the lasing threshold and into its linear mode of operation. For fastest modulation capability, e.g., in the multi-gigaHertz regime, the VCSELs are biased above the lasing threshold to take advantage of the fast stimulated-emission based response times.
The main contributors of power dissipation in a typical (biased) VCSEL based system are the constant current bias through the VCSEL, the magnitude of the signal current applied to the VCSEL element and the energy required for the supporting driving circuits.
Further, in optical interconnects, manufacture and alignment techniques may require accurate positioning of the interconnect components. This active positioning can be facilitated by active alignment techniques.
Lower power dissipation is almost always desirable. The need for lower power dissipation is even further accentuated in cryogenic application (such as, intra-Dewar environments). In a Dewar environment, traditional optical data links become prohibitive due to the undesired thermal load contributions to the cold side of the Dewar system.
Based on the above, there is a need to provide a circuit for driving a VCSEL based optical link while dissipating very low levels of thermal energy.
There is also a need to provide a low power driver circuit suitable for high density optical interconnects and thermally sensitive applications such as in cryogenic Dewars.
Furthermore, there is a need to provide a low power circuit and optical interconnect modulation scheme for driving Light Emitting Diode (LED) based optical interconnects.
There is also a need to provide a low power circuit and optical interconnect modulation scheme.
There is also a need to provide a low power circuit that provides for active alignment.
There is also a need to provide a low power electronic driver circuit and optical emitter.